<!doctype html>
<html>
<head>
<meta charset="utf-8">
</head>
<body><span class="red">body</span>元素</body>
</html>
<script type="text/javascript">

var b = document.documentElement.lastChild;
b = document.documentElement.firstChild.nextSibling.nextSibling;

var text = document.documentElement.lastChild.firstChild.firstChild.nodeValue;


console.log(b.nodeName);
console.log(text);

</script>

